Search Documents

By Sydney Mantsho, Toni Streczynski, Manuel Gonzalez

"In 2013, the commissioning of the MillStar Stabilisation and FloatStar Stabilisation and Optimisation controllers were completed at the Cerro Bayo Silver (Ag) mine in Patagonia, Chile. The MillStar control system has stabilised the feed to the SAG mill as well as the density at the discharge end of the SAG mill and ball mill. The FloatStar Stabilisation and Optimisation controllers have successfully stabilised and optimised the flotation circuit to ensure consistent product quality within desired specifications.The mill feed is controlled utilising the MillStar Solids Feed controller. Additionally, the solids to liquid ratio into the SAG mill was controlled utilising the Mill Inlet Ratio controller in conjunction with the Solids Feed controller. The discharge end of the milling process is a highly interactive and complex system. The use of a Robust Nonlinear Model Predicative Controller (RNMPC) was ideally suited to control this section of the process. On the Cerro Bayo milling circuit, the RNMPC was used to control the mill discharge sump level and the primary cyclone feed density to produce a more consistent feed to the flotation circuit.Three levels of the FloatStar control system were installed, for flotation stability, concentrate flow stability as well as grade optimisation. The Level Stabiliser was used to stabilise the level control on 6 flotation banks. The Flow Optimiser was commissioned on the Rougher, Scavenger and Cleaner concentrate sumps to stabilise concentrate flow from the flotation cells. The Grade Recovery Optimiser was commissioned on the Roughers section. A number of instrumentation challenges were identified which limited the overall benefit derived from the system. Once these were addressed, the performance was optimised. The overall benefit provided by the system was observed in terms of the improvements in Ag recovery."

Jan 1, 2014

By L. G. Wang

The stability of foams and froth plays an important role in flotation, in which small amounts of relatively weak non-ionic surfactants (frothers) are used to produce air bubbles and foams. In the present work, factors affecting the stability of the foams produced in the presence of common frothers, such as n-pentanol, n-octanol, methyl isobutyl carbinol (MIBC), and polypropylene glycol (PPG), have been studied. We used the thin film pressure balance (TFPB) technique of Schelud-ko-Exerowa type to measure the equilibrium film thicknesses. The results were used to determine the contributions from the various surface forces to the disjoining pressures in the thin lamellae (foam) films formed between air bubbles. In addition, we used a model developed by Wang and Yoon (Colloids and Surfaces A: Physicochem. Eng. Aspects, 2006) to calculate the elasticities of the lamellae films at the critical thicknesses at which films rupture. The surface forces and elasticity da-ta were then compared with the foam stabilities in the presence of the various flotation frothers. It was found that foam stabilities are controlled by both film elasticity and surface forces, the relative contributions of which change with frother type and concentration. In general, surface forces play a more important role at relatively low frother concentrations, while elasticity plays a more important role at higher concentrations. At the frother additions usually employed in the mining industry, MIBC relies on surface forces while PPG-400 relies on film elasticity in producing stable foams. The former is capable of dampening the hydrophobic force, which is a major attractive force destabilizing lamellae films, while the latter is capable of reducing surface tensions at low concentrations.

Jan 1, 2014

By Dianyin Liang, Hongxiang Ran, Xiaoming Wang, Xiaoou Xia

"This paper presents a new magnetic separator, which can be applied to increase the grade of fine magnetite ore feeding of ball mill. This innovative equipment possesses a rotating magnetic system and has a magnetic field of rapid polarity change which can strengthen the destruction of magnetic agglomerations and the dispersion of minerals to improve the quality of separation. Now this type separators have been successfully applied in several large concentrating plants such as Shuichang Iron Mine under Shouang Mining Company in China. Finally, this paper outlines practical results focused on feed grade and tailing yield, the results are showing that the quality of feeding can be improve tremendously. Hence, a new generator of rotating magnetic field has been paved. INTRODUCTION Jidong region in China is the important origin of iron ore, the characteristics of the iron ore in this region is low grade and complex, the iron mine discharges fine powder tailings reaches tens of millions of tons each year, in the wind action easy to form sand, this poses a threat to the atmosphere environment of Beijing. In order to reduce the mixing of large amount of useless ore and reduce the energy consumption of mill operation, a high efficiency pregrinding equipment is needed. Rotating magnetic field separator (RMS) is an advanced equipment, the main advantage of RMS is the significant reduction in particle entrapment and can easily break magnetic agglomeration. This reduction is so significant that RMS is capable of operating very close to theoritical limit for separator precision and can increace efficiency in selection process.Some expenrimental work on dry rotating magnetic field separation has been carried out in July 1998 in the company Ka Pty Ltd, then in 2008 BGRIMM developed industrial separation XCTG0816 in Shandong province . The wet RMS was researched in1960s in Former Soviet Union and the first industrial equipment was developed by BGRIMM in 1970s,then in 1990s wet RMS was applied in Ansteel group corporation. In 2017,6 units large wet RMS (SXCT1230)which were the largest RMS was applied in Sichuan province. No matter wet RMS and dry RMS, although they are used in differenct applications, they have some common research.in addition ,they all have good use effect."

Jan 1, 2018

By V. Grujic, M. Grujic, D. Salatic

"Two areas are involved in the research work of the comminution process (crushing and grinding). The first one involves the changes of the size class distribution values that are definded by the differential equations in the function of the ore property and working conditions. The second area involves the comminution of the different levels in order to optimize the working parameters and to decrease the operational costs in the grinding process.We have studied, in detail, the possibility of functioning the crusher at the maximal loading, over 4500 kN, ball mills with diameters larger than 5.0 m and semiautogenous mills with diameters larger than 10.0 m.Using the computers, we have achieved the maximal loading range of the crusher, over Fc ? 4500 kN in the crushing process. In the grinding process, using the adequate differential equations in the automation process, we have established the correlation between the pulp mass capacity in the mill, pulp dencity, ore fineness in the pulp and recirculating ore charge.With the appopriate text, equations and graphs, this paper shows the results of our several years research work in the laboratory and in the ore comminution plant of Majdanpek Copper Mine."

Jan 1, 2003

By F. C. Araújo, T. Tavares, J. Leite

"This work presents the small-scale mining cluster of kaolin in Rio Grande do Norte (RN) and Paraiba (PB), both Brazilian states, including the following information: number of companies, process flowcharts, production numbers, mineralogical (XRD) and chemical (XRF) composition, granulometric distribution (screen and laser granulometer) and image analysis (SEM). Some social indicators in the region of the RN and PB States are presented in association with these data. The number of companies and their flowsheet were obtained through in situ visits and sample collection for technological characterization. The comparative study of the different flowsheets for kaolin production in the world was done using the databases and presenting the state of the art of kaolin processing. The results indicated that the mean feed typically contains 35-39% kaolin with quartz, muscovite and kaolinite as main mineralogical components and SiO2 (65.83%), Al2O3 (21.19%), K2O (3.9%), and Fe2O3 (0,63%) as main chemical constituents. The products of mineral processing are twofold, one between 74 µm and 37 µm, and the other smaller than 37 µm. The wastes of operation had major quantities of kaolin. The average Human Development Index (HDI) of the cluster region is approximately of 0.61, which shows an association between mineral processing plant and social indicators. The kaolin recovery, however, is between 30-55% for the three most common types of flowsheets that are currently used in the small kaolin mining cluster, indicating a need for technological improvement to achieve regional development. These data could be used incrementally to adapt the process plant currently used in the small-scale mining cluster of kaolin."

Jan 1, 2014

By Lj. D. Andric

By the micronization-milling of the material, the size and the structure of its particles are changed and it comes to the increasing of the potential energy of the system as well as to the chem-ical activity of the material what is the result of an increased free surface and of the concentration of the grate defects, that is of the internal energy of the system. All these changes that are reached, show that new characteristics of treated materials are got by micronization process. Controlling the process of the micronization and by purpose directing of the new characteristics of the activated materials, we can have the positive effects and use them in more technologies. Talc is important nonmetallic mineral raw material that is widely used as either the basic raw material, or as filler. This has stimulated its technological investigation, as well as the investigation of its physical-chemical characteristics. In this paper are shown experimentally reached results of the physical-chemical characteristics of the talc during the process of the micronization in high energetic mill. In this paper, the optimum conditions of miconization of talc in high-energy-speed rotary mill and its influence micronization on a degree of Fe2O3recovery by hydrometallurgical methodes, are presented. The X-ray analysis of the obtained products showed that high quality talc with low content of can be obtained by these physical-chemical processes In this paper, the principles and application or fine and ultra-fine grinding high-energy attriton mill with small balls, enabling fast, efficient grinding, low energy consumption, short grinding time and easy handling will be described.

Jan 1, 2014

By A. J. Lynch, D. K. Tungpalan, Y. Reja, E. C. Avelar, G. Figueroa, S. Gómez, R. Alanis, M. A. Corona-Arroyo

"Have you been on a mine site? This question was posed by Emeritus Professor Alban Lynch to Higher Degree by Research (HDR) Students from the Sustainable Minerals Institute - Julius Kruttschnitt Mineral Research Centre (SMI-JKMRC) in the Student Technical Presentations in 2015. From that question, five HDR students from SMI-JKMRC organised a placement on mine sites in Mexico. The SMI-JKMRC is well known for its tradition to provide their students with opportunities to enhance and test their skills in mineral processing plants. The Student Venture became a short internship for HDR students which had the objective of establishing collaboration with mining companies in Australia and overseas, and of providing a unique experience for the HDR students in regard to their training, professional development, networking and cultural interchange. In return for the companies’ support, the students conducted plant audits to evaluate the process performance thereby providing valuable data to the host company. The 2016 Student Venture was held at the Grupo Peñoles & Grupo Fresnillo in Mexico, in which three mine sites received five HDR students from JKMRC and one young researcher from Universidad de Guanajuato (UG). This paper describes the positive outcomes for the mining company and the students for this experience. The Venture was considered very successful, as it provided valuable training for the students as well as in depth information about the operation of the comminution and flotation circuits of the host sites for the Grupo Peñoles & Grupo Fresnillo. The experience also provided an opportunity for an exchange of knowledge between the HDR students and the site personnel from the host operations. The indication of the success of the experience for all involved was the support of the host company in future student internships."

Jan 1, 2018

By Jorge Misle, Daniel Silva

"This paper addresses the need for advanced control technologies and strategies in the mining industry, its potential and actual impact on mining processes and the best practices for their implementation, operation, and long term sustainability. It is well known that advanced process control (APC) can be a very good source for incremental process improvement for the mining industry, yielding to higher production rates or helping maintain consistent production rates despite ore changes. The application and integration of new technology, process knowledge and innovation are key elements in building such a supporting structure. More specifically, and this cannot be emphasized enough, the correct application and assembly of control tools, the in-time presentation of key data to decision makers and the development of relevant statistics and KPI’s (key performance indicators) can and will make a difference not only in terms of production, but also in plant stability, availability and production costs. In deploying such ideas and aiming at the long-term goal of "Operational Excellence", Minera Los Pelambres (MLP) has developed a number of successful control strategies, best practices and technologies, which are not only the application of state-of-the-art automation and computing tools, but rather the assembly of the above presented structuring factors. This work discusses some of the key tools and ideas implemented for SAG & Ball milling and Flotation areas, their performance results and the roadmap taken for the integration of process knowledge and control tools. Also, cases studies are presented and discussed further to not only show the main areas of improvement, but also to highlight the benefits of such strategy that for the most part, deviate from the traditional mining industry control approach. Also, a word is given on the need for innovating in the design of control strategies and leveraging best practices and process knowledge that ultimately, will contribute to long-term reliable operations, improved mineral processing and, although unmeasured, lead to a superior overall performance and productivity of all mining personnel involved."

Jan 1, 2014

By Johannes Käppeler, Alexander Weh, Harald Giese, Klaas van der Wielen

"High voltage breakage is a novel comminution technology that shows considerable potential for various applications in mineral processing and recycling. It relies on highly energetic electrical pulses to induce electrical explosions in rocks, causing the formation of plasma channels and powerful shockwaves that result in fracturing and fragmentation of particles. There has been considerable interest in this technology for its ability to weaken rocks and preferentially liberate target minerals, as previously demonstrated by other authors. Weakening has the potential to significantly reduce energy consumption during comminution, or alternatively, increase throughput of a circuit. Better liberation may yield an improved concentrate grade and/or recovery, reduce fines losses to tailings or increase the grind size required for liberation, thereby also reducing energy requirements. This review aims to increase general awareness of this technology, and promote further research into it by providing a general summary of the theory underlying high voltage breakage, as well as the envisaged applications of this novel technology. A brief history of the technology is presented before progressing onto the physics underlying the electrical and geomechanical aspects of high voltage breakage. Key results regarding weakening and liberation are discussed, and some mention is made of current challenges and planned developments to increase the throughput of high voltage breakage units to the level where it can be integrated into new and existing processing circuits."

Jan 1, 2014

By David Verrelli, Melissa Kistner, Leanne Smith, Chris Aldrich, Lidia Auret, Warren Bruckard

In this investigation, different mixtures of realgar and orpiment particles were floated in a laboratory batch flotation cell and multivariate image analysis was used to estimate the arsenic content in the froths. The analysis was based on the froth colour, as well as extraction of three groups of textural features, namely those based on grey level co-occurrence matrices (GLCMs), wavelets and local binary patterns (LBPs). Collectively, these features provided better information on the arsenic content of the froths than any one of the individual groups of features. Partial least squares models could explain approximately 78% of the variance in the arsenic by using all the features combined. The colour content, particularly the green component in the red-green-blue (RGB) features, provided almost as much information as each of the three sets of texture-base features individually.

Jan 1, 2014

By Bruno Miotto, Rômulo Faria, Juliano Tessinari

Water has become a scarce resource in quality. Companies in the ornamental stones sector use water intensively in their processes. Given the current situation, it is imperative to rationalize this feature that at first is related to the reduction of consumption, through no waste. Considering the importance of environmental preservation of this resource and also to comply with the legislation that governs the procedure for processing of ornamental stones, new alternatives should be available for the maintenance of current activities and promoting the development / growth of the sector on the principles of environmental sustainability and economic in future scenarios. The ornamental stones processing industries, especially for micro and small enterprises, require the implementation of a management program that optimizes the use of this feature, since the techniques individually processed operate with three basic processes dependent on water use: split blocks, polishing and finishing slabs. This technology requires a large volume of water resources and control measures involving operating recirculation water can minimize power consumption, making the company more profitable and sustainable. This is a survey of literature, associated with technical reports provided by partner companies and government agencies. This study aimed to the organization and provision of theoretical knowledge about the subject matter coupled with management practices, which may be reproduced or re-purposed in ornamental stones processing companies. It should be noted that the industry in question is lacking in technical expertise for the implementation of sustainable attitudes relevant to water reuse.

Jan 1, 2014

By D. DePaoli, P. Zhang

"Phosphate ore is one of the most significant secondary resources for rare earth elements (REEs), and Florida phosphate is of particular interest due to its much higher ratio of heavy REEs, especially yttrium. Analyses of numerous samples from different phosphate processing streams in Florida showed that heavy REEs account for about 50% of the total REEs in Florida phosphate with yttrium accounting for approximately 30%. It was estimated that the amount of yttrium from US phosphate processing could meet the world demand for this critical element. This research aimed at recovering both REEs and phosphorus from a phosphate flotation tails. This tails is composed of mainly silica and phosphate with a small fraction of heavy minerals including monazite and xenotime. Since the specific gravity of silica is 2.6 versus 3.2 for phosphate and 4.5-5 for rare earth minerals, pre-concentration of the minerals of interest by gravity separation was investigated first. A pilot scale shaking table was used in this study. One pass gravity concentration achieved a shaking table concentrate analyzing over 600 ppm REEs at about 40% recovery. Flotation of the shaking table concentrate resulted in a product containing 1809 ppm REEs and 26.37% P2O5 with corresponding recoveries of 73% and 82%. Sulfuric acid leaching at 75oC could recover over 60% REE and nearly all the P2O5. Higher REEs (>90%) recovery was achieved by conducting leaching at higher temperature with concentrated sulfuric acid. The phosphoric acid from leaching of the flotation concentrate is of superior quality compared with that generated from regular phosphate rock.INTRODUCTION Rare earths are a group of 17 elements including those of the lanthanum series, as well as the non-lanthanides, yttrium and scandium. These elements have very specific critical uses in a multitude of markets. For example, lanthanum is used as a catalyst in breaking down crude oil to produce gasoline, diesel and jet fuel and neodymium is the core magnetic component in high-strength magnets for electric car batteries, wind turbines and hard disk drives. Rare earths are also essential for many military applications. Many of these applications have no substitute materials and the move to green technologies has dramatically increased their demand."

Jan 1, 2018

By Dominic Howarth, Diana Drinkwater, Don McKee

"The pressures on mining and minerals education at the tertiary level are well known. Within Australia, for example, the number of undergraduate mining engineering courses with 30 or more students in each year has reduced to three (University of Queensland, University of New South Wales and Curtin University). Similar declines in both student numbers and participating institutions are evident in many other parts of the world, and notably in USA and most countries in Europe.An in depth study of the Australian sector was conducted in 1997/1998, resulting in the Back from the Brink report (Carter 1998). The Australian situation was summarised as follows.Australia’s minerals education system, in its current form, is fragile and is in no position to seize the opportunity (i.e. world leadership in minerals education) and is more likely to succumb to the threat.Current trends include:- an acute shortage of talented academic staff, as a result of University remuneration packages having become hopelessly uncompetitive with those in the minerals industry;- small student populations and high relative costs, making mineral specific courses vulnerable to closures, when Universities are under extreme cost pressures; this situation will be exacerbated if enrolments drop in response to, say, a cyclical down turn in the industry; and- under-resourcing of minerals departments because of their comparatively small size, making these departments incapable of delivering top class teaching in all aspects of their courses, despite being excellent in some areas.Most of the Australian issues identified above have direct parallels in other countries.The most common response of institutions to the threats is to seek strength, and in some cases survival, through various forms of linkages and networks. A number of these associations, which are frequently defensive in nature, are outlined in the paper."

Jan 1, 2003

By Hiroshi Sasaki, Herman D. Mendoza

"The surface-chemical property of nickel slag fiber was modified in aqueous media in order to act as an active and efficient collector of colloidal amorphous silica from geothermal effluent. Colloidal amorphous silica (0.05 µm) from geothermal wastewater causes operational and ecological problems. It clogs geothermal pipes and waterways, and when disposed to the environment poses hazardous effects on both the flora and fauna ecology. Because colloidal amorphous silica is extremely fine and remains in suspension in aqueous media, conventional solid/liquid processes to remove colloidal silica from its bulk liquid are rendered ineffective.A rapid separation technique is then developed to remove effectively amorphous colloidal silica from its bulk liquid by attaching the extremely fine particles of silica onto a nickel slag fiber coated with magnesium hydroxide, Mg(OH)2. The nickel slag fiber has the following characteristics: a high surface area and predominantly possesses negative charge in aqueous media with an iso-electric point at pH ~2.5. When soaked and saturated with Mg(OH)2 solution, the surface of the nickel slag fiber becomes coated with fine and compacted Mg(OH)2 precipitates. This modifies the surface- chemical property of nickel slag fiber transforming the negatively charged surface into a positively charged surface in aqueous media with an iso-electric point of around pH 11.8, which corresponds to the iso-electric point of Mg(OH)2. When geothermal effluent containing negatively charged colloidal amorphous silica particles (i.e.p. of silica is pH 2) is passed through a column-bed packed with surface-chemically modified nickel slag fibers under natural pH conditions, the colloidal amorphous silica particles are recovered by attachment onto the surface of the surface- modified nickel slag fiber. The recovery of colloidal amorphous silica by attachment is 97-99%, resulting in the production of a relatively clean and silica free output. Aluminum hydroxide, Al(OH)3, was also used to modify the surface –chemical property of the nickel slag fiber. In the same way, it also exhibited a positive response with the collection of colloidal amorphous silica from its bulk liquid, but yielding a lower recovery of 90%. This may be attributed to the lower surface potential and iso-electric point of pH 9.3 for Al(OH)3. The separation process was evaluated and analysed using existing potential energy theories. Figure 1 shows a micrograph of the surface of an unmodified and the Al(OH)3 –modified surface of nickel slag fiber."

Jan 1, 2003

By Mary Stewart, Jim G. Petrie, Geoff Brent

"Life Cycle Assessment (LCA) is gaining increasing acceptance as a decision-support tool by which to evaluate the environmental performance of a product, process or service. This is evidenced by its inclusion in international policy documents (for example in the European Union’s Integrated Product Policy) and in environmental management standards (the ISO 14 040 series of environmental management codes relate to LCA). In response to this, the minerals industry has conducted a number of commodity-specific LCAs. These include studies for global production of a number of commodities including copper, nickel, aluminium and steel. In addition, a number of minerals companies profess to use LCA as part of their suite of project and technology assessment tools. Often, this collected use represents more a situation of “we do this because we’re told it’s good for business” rather than from any demonstrable evidence of this fact. This has led to a situation of much confusion and disillusionment within the industry, exacerbated by the obvious current limitations of LCA to accurately reflect the environmental performance of minerals and metals.Our point of departure here is that LCA, conforming as it does to the tenets of environmental systems analysis, is a valuable starting point, and that there is merit in exploring to what extent the methodology can be enhanced to better reflect the environmental performance of minerals and metals. Specifically, we explore here the further development of LCA to address the following:• Land Use issues• Consumption of Abiotic Resources including metallic and non-metallic minerals, water and soil)• Human and Eco-toxicity issues relating to mobility and bio-availability of metals• Salinityand address these through selected experimental and simulation case studies relating to energy- and base minerals production. Advances resulting from the United Nations Environment Programme/Society for Environmental Toxicology and Chemistry Life Cycle Initiative are presented in that they directly affect the application of LCA to mining, minerals and metals. Comments are offered on how best the mining and minerals industry might interface with future developments resulting from this Initiative in order that the Initiative can deliver outcomes which render LCA a useful tool for decision making in mining and minerals processing."

Jan 1, 2003

By Jim Petrie, Mary Stewart, Damien Giurco

This paper describes a generic approach to analysing the environmental and economic performance of a generic global mineral/metal value chain, with the express view of improving the quality of prospective decision-making within the industry in order to ensure more sustainable outcomes. As a point of departure we propose that it is not possible to place metals in the context of the sustainable development of society without paying due regard to the entire metals value chain. Thus, the starting point for this analysis is the development of a global stocks flows and transformations model, for the metal of interest. Any aspect of the value chain, e.g. “metals refining, “goods manufacture”, “use and disposal”, can be assessed, either relative to other stages in the value chain, or in more detail by focusing on the technologies used within that stage. The use of this model as a decision support tool is explored here for the case of copper. Both primary and secondary production routes are enumerated, covering a range of processes, for seven distinct geographic regions around the globe. The value of the modelling approach is explored for different energy mixes. In particular, the case study examines the impact of increased recycling on the (re) distribution of global and regional environmental impacts for technologies-in-place in these different regions. The aim of these case studies is to highlight to the minerals processing and metals refining industries their potential role in a more sustainable global society.

Jan 1, 2003

By R. Venugopal

The paper reviews the development of Mineral Engineering education and training programmes in India. It highlights the major academic programmes and describes the evolution of the curriculum and design of courses in response to the changing requirements of India?s mineral and coal industries. An outline of the efforts needed to sustain and further improve the existing programmes is also provided. Keywords: manpower, mineral engineering

Sep 1, 2012

By Wei Sun, Ruolin Wang, Jianjun Wang, Xiaodong Li, Honghu Tang, Yuehua Hu, Anh V. Nguyen, Haisheng Han, Kefeng Chen, Zhao Wei

It is difficult to separate scheelite especially from fluorite with fatty acid collectors because the adsorption mechanism of these collectors occurs through chemisorption of the oleate ion onto the mineral surface. A simplified flotation process using Pb-BHA complexes was developed to replace the energy-inefficient Petrov’s process of using a fatty acid, increasing the recovery of scheelite and reducing the cost. The relationship between surface chemical properties (crystal chemistry, solubility, and Zeta potential) of minerals and flotation by using a fatty acid or Pb-BHA complexes was studied in detail to provide new insights into the selective separation mechanism. The results indicate that the scheelite surface exposes more O atoms than Ca and that they are negatively charged due to the anisometric dissolution of Ca and WO4, which provides the possibility for separation using selective interfacial reaction. The FTIR and Zeta potential results indicate that both chemical and electrostatic adsorption play an important role in the adsorption of Pb-BHA complexes on the scheelite surface. The XPS results of the atomic composition and binding energies confirmed the presence of the adsorbed Pb-BHA complexes and that O and Ca may be the active adsorption sites. Therefore, scheelite was able to be collected by forming either a Ca-O-Pbcollector or W-O-Pb-collector (BHA). However, fluorite was only able to be collected by a fatty acid collector and colloidal [H2SiO3]n -, and a high temperature was needed improve the selective desorption of the adsorbed fatty acid collector by forming Ca-[H2SiO3]n - on the fluorite surface, resulting in serious problems in industry. However, the Pb-BHA complexes significantly contribute to improving the recovery of scheelite minerals, simplifying the flotation process, and circulation of the residual reagents and water. The new process has been applied in Shizhuyuan Mine, and improved the recovery by almost 10%.

Jan 1, 2018

By Kevin Galvin, Simon Iveson

Fine particles are the most valuable because they are the most liberated. However, they are also the most expensive and difficult to recover and concentrate. The Reflux Classifier is a novel invention that combines many of the virtues of existing fine particle separation technologies in a way that provides profound synergies. Multiple parallel narrow channels create a laminar-shear separation zone. The laminar flow provides a well-defined velocity gradient that exposes particles on the wall to a conveying velocity that is approximately proportional to their size, thus reducing the dependence of elutriation velocity on particle size. The high shear rate in these channels generates a hydrodynamic lift force that selectively lifts low-density particles off the channel wall and thus causes them to be preferentially conveyed out in the overflow. Particles that are not elutriated slide back down into the mixing reflux zone beneath the inclined channels which gives them multiple opportunities to re-enter the channels. The resultant suspension of both coarse and fine high-density particles in the fluidized bed zone at the base of the unit generates a strong autogenous dense medium that helps to direct large low-density particles back up to the overflow. The fluidization water also simultaneously de-slimes the high density underflow product. When placed in a centrifuge, the benefits of these features multiply with the improvements in capacity and selectivity that arise from high G-forces. When inverted, these features can be used to perform flotation well beyond the conventional flooding limit. Hence this invention platform has the potential to dramatically improve both gravity and flotation separation performance across the minerals processing industry.

Jan 1, 2014

By Montaser S. EL Salmawy, Takahide Wakamatsu, Eishi Kusaka

"In conventional flotation, fluoride ions selectively would react with the aluminum site on the microcline surface and produce negative charged sites for amine to be adsorbed (Smith, 1976). According to this view, aluminum site is considered as a key feature in feldspar flotation. Generally, fluoride ion has been widely used as a modifying agent in silicate flotation. Since O'Meara's patent appeared on HF -amine reagent system to selectively float feldspar from quartz in 1942, relatively few contributions have been devoted in this issue. The reason might be that the process works very well, and accordingly there is no initiative to investigate in this area. However, due to the awareness of international community to restrict using of hazardous reagents like HF, sound engineering practice to search for alternative methods, not utilizing HF, has been launched. Inspection of literature, one can find several works dealing with this issue.In this contribution, the effect of ethoxylation of long chain alcohols on the quartz and feldspar flotation behaviors was investigated for surfactants of the octylphenol polyoxyethylene family. The tests were carried out with an average of 7.5 (Triton X 114), 9.5 (Triton X 100), 30 (Triton X305), 40 (Triton X 405) and 70 (TritonX 705) oxyethylene units. Electrokinetic and flotation studies on quartz have shown that at low pH values, quartz could be floated with polyoxyethylene octytlphenols. The possible mode of adsorption of these nonionic surfactants may be suggested to be due to hydrogen bonding between the oxygen of ether and hydrogen in the free hydroxyl groups on quartz surface. It was anticipated that the selectivity between quartz and microcline would decrease as oxyethylenic chain length increases."

Jan 1, 2003